Two more slides to give a feel for the scale of a state-of-the-art wind turbine. First, a nacelle . . .
. . . And second, a blade.
Wind EnergyResource, Advantages, and Constraints Ashutosh Singh B.Tech 4th Year HIT
Renewable Resources and Technologically Viable End-usesWind - electricity and No Greenhouse Gas Emissions hydrogen production Insurance Against Conventional Fossil- based Price Risk No Sulfur Dioxide (SO2), Nitrous Oxide (NOx), or Mercury Emissions
WIND POWER - What is it?• All renewable energy (except tidal and geothermal power), ultimately comes from the sun• The earth receives 1.74 x 1017 watts of power (per hour) from the sun• About one or 2 percent of this energy is converted to wind energy (which is about 50-100 times more than the energy converted to biomass by all plants on earth• Differential heating of the earth’s surface and atmosphere induces vertical and horizontal air currents that are affected by the earth’s rotation and contours of the land WIND. ~ e.g.: Land Sea Breeze Cycle TURBINES
Why Wind Energy? Wind, for now, is the renewable energy resource/technology of choice “Free” resource A “clean” resource due to: Replacement of a “dirty” energy source (coal) and, No emissions associated with its use Can be utilized on underutilized land or on lands currently in commodity crop production (“harvest” on the surface and “harvest” above the surface)Will primarily be used for electricity generation for immediate end-use or as a “driver” for hydrogen production
Energy Production and the EnvironmentEnergy use in power plants accounts for: 67% of air emissions of SO2, the primary cause of acid rain. SO2 causes acidification of lakes and damages forests and other habitats. 25% of NOx, which causes smog and respiratory ailments. 33% of Hg (mercury), a persistent, bio-accumulative toxin which increases in concentration as it moves up the food chain, e.g. from fish to birds, causing serious deformities and nerve disorders. SOURCES: Union of Concerned Scientists (UCS)
Wind Energy BenefitsNo air emissionsNo fuel to mine, transport,or storeNo cooling waterNo water pollutionNo wastes
Wind Resources India The Wind Resource Assessment in India estimates the total wind potential to be around 45 000 MW (mega watt). This potential is distributed mainly in the states of Tamil Nadu, Andhra Pradesh, Karnataka, Gujarat, Maharashtra, and Rajasthan.
Tamilnadu Wind Potential Tamilnadu is one of the three best wind states in the country The wind installed capacity of the state is 6548MW as on 31.10.2011. This is 47% of the country’s total wind installed capacity.Most of that potential probably won’tbe developed . . .
Wind Energy Basics Physical & Engineering Aspects
Wind Power Equation P = ½ * air density * Area Swept by Rotor * Wind Speed 3 P = ½ * ρ * A * V31) Power in the wind is correlated 1:1 with area and is extremely sensitive to wind speed (the cubic amplifies the power significantly)2) If the wind speed is twice as high, it contains 2 3 = 2 x 2 x 2 = 8 times as much energy3) A site with 16 mph average wind speed will generate nearly 50% more electricity and be more cost effective than one with 14 mph average wind speed (16*16*16) / (14*14*14) = 1.49274) Therefore, it “pay$” to hunt for good wind sites with better wind speeds
Energy from the Wind Turbine output drives wind economics and output is a strong function of wind speed Wind speed increases with height above the ground Power = 1/2 × (air density) × (area) × (wind speed) ³ Energy in the wind increases as height increases (theoretically) V2/V1 = (H2/H1)1/7
Turbines: Different Sizes and Applications Small (≤10 kW) • Homes (Grid-connected) Intermediate • Farms • Remote Applications (10-500 kW) • Village Power (e.g. battery changing, water pumping, telecom sites) • Hybrid Systems • Distributed Power Large (500 kW – 5 MW) • Central Station Wind Farms • Distributed Power • Offshore Wind
Large Wind Systems Range in size from 100 kW to 5 MW Provide wholesale bulk power Require 13-mph average wind sites
Typical Turbine Size 1.3 to 1.8 MW rated capacity Rotor diameter 60 to 80 meters Tower height 60 to 80 meters Turbine footprint 10 m x 10 m 245-330 ft. TIP 165-220 ft TOWER Lowest ground clearance is at least 100 ft. Apx. 100 ft.
Variability Quantifying Wind Power Performance 99% Availability >90% Operating Time* 30 – 40% Capacity Factor* Lake Benton, Minnesota Analysis of Windfarm Operation
Expected Output/Capacity Factor The capacity factor is simply the wind turbines actual energy output for the year divided by the energy output if the machine operated at its rated power output for the entire year A reasonable capacity factor would be 0.25 to 0.30. A very good capacity factor would be 0.40 Capacity factor is very sensitive to the average wind speed
Power CurvesThe turbine would produce about 20% of its rated power at an average wind speed of 15 miles per hour (or 20 kilowatts if the turbine was rated at 100 kilowatts).
“Value” of Wind Energy The value of a wind turbine or wind farm depends upon many factors location terrain wind speed = f(location, terrain) cost of competing energy source rate structure of competing energy source
Wind Insures Against Fuel Price Risk It is estimated that Value of domestic fuel generating electricity from source (wind) would have renewable sources can a direct benefit on the ultimately save community. consumers more than Rs.300/MWh . Wind energy “Fuel” is inflation-proof; therefore impervious to fuel price hikes
Wind - Natural Gas Comparison Wind Natural GasLow Operating Cost High Operating CostsHigh Capital Cost Low Capital CostNon-dispatchable DispatchableNo Fuel Supply/Cost Fuel Supply/Cost Risk Risk Smog, GreenhouseNo Emissions Gas Emissions
Wind Power Costs Wind Speed Assuming the same size project (total MW installed), the better the wind resource, the lower the cost capture more energy for the same maintenance cost.
Wind Power Costs Project Size Assuming the same wind speed, a larger wind farm is more economical; economy-of-scale associated with wind farm installation
Wind Power Isn’t Perfect Wind Power output varies over time; it isn’t dispatchable Wind Power is location-dependent (rural vs. urban where it is needed most) Wind Power is transmission-dependent for tie-in to the grid Wind Power has environmental impacts (pro / con) Wind Power can only meet part of the electrical load
Common Misunderstandings Wind turbines are only generating electricity about one third of the time.Wind turbines generate electricity essentially all the time, but only at their rated capacity about 30- 40% of the time